This invention relates to olefin polymerization, polymerization catalyst systems, and processes to prepare polymerization catalyst systems.
Supported chromium catalysts have long been a dominant factor in the production of olefin polymers, such as polyethylene. Chromium-containing compounds, either supported or unsupported, can also be used to oligomerize olefins. Unfortunately, the production of chromium-containing compounds for use in catalyst systems, usually results in some waste product which contains chromium compounds. Chromium-containing compounds are and have been considered environmental and animal toxins for the past several decades. Therefore, elimination, reduction, or utilization of recyclable chromium-containing compounds is desirable.